Impact Loads Identification in Standoff Metallic Thermal Protection System Panels

This article describes two experimental approaches for the identification of transient impact loads applied to a metallic composite thermal protection system (TPS) panel. The critical nature of the TPS to the survival of the vehicle and crew warrants the development of a technique that can detect, quantify, and locate transient impact loads. This information will provide an opportunity to identify specific panels that are more or less prone to damage from transient impacts. Furthermore, a historical database of impact loads encountered can be retained for use in the development of statistical models that relate impact loading to panel life. The two techniques presented herein are a physics-based approach, where the panel is assumed to behave as a rigid body at low frequencies, and an inverse frequency response approach, where the system impedance matrix is measured, from which the loads acting on the panel can be estimated using the measured response. The validity of approaches is verified experimentally, and it is shown that the inverse frequency response method is capable of detecting, locating, and quantifying transient impact loads to a high degree of accuracy.

[1]  S. S. Law,et al.  Moving loads identification through regularization , 2002 .

[2]  D. T. Greenwood.  Principles of dynamics , 1965 .

[3]  Tommy H.T. Chan,et al.  Moving Force Identification based on the Frequency-Time Domain Method , 2003 .

[4]  J. A. Fabunmi,et al.  Effects of structural modes on vibratory force determination by the pseudoinverse technique , 1986 .

[5]  T. G. Carne,et al.  Force Reconstruction Using the Sum of Weighted Accelerations Technique-Max-flat Procedure , 1993 .

[6]  Jdc Crisp,et al.  On the Identification of a Harmonic Force on a Viscoelastic Plate From Response Data , 1992 .

[7]  A time domain method for identifying dynamic loads on continuous systems , 1991 .

[8]  Robert E. Seydel.  Impact identification of stiffened composite panels , 2000 .

[9]  E. G. Yanyutin,et al.  Identification of the Impulsive Load on an Elastic Rectangular Plate , 2003 .

[10]  Brenda Hillary.  Indirect measurement of vibration excitation forces , 1983 .

[11]  Fu-Kuo Chang,et al.  Impact identification of stiffened composite panels: I. System development , 2001 .

[12]  Estimation of Rigid Body Frequency Response Function Matrices via Redundant Perimeter Reference Measurements , 1995 .

[13]  S. S. Law,et al.  Identification of moving loads on a rectangular orthotropic plate from strains , 2001 .

[14]  J. Verhoeven.  Excitation Force Identification of Rotating Machines Using Operational Rotor/Stator Amplitude Data and Analytical Synthesized Transfer Functions , 1988 .

[15]  Keeyoung Choi,et al.  Identification of Impact Force and Location Using Distributed Sensors , 1996 .

[16]  Tommy H.T. Chan,et al.  Moving force identification: A time domain method , 1997 .

[17]  F. Chang,et al.  Impact identification of stiffened composite panels: II. Implementation studies , 2001 .

[18]  Fu-Kuo Chang,et al.  Identifying impact load in composite plates based on distributed piezoelectric sensor measurements , 1996, Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[19]  Youn-sik Park,et al.  Error analysis of indirect force determination and a regularisation method to reduce force determination error , 1995 .

[20]  R. R. Heldenfels,et al.  The NASA structures and materials research program for supersonic cruise aircraft , 1976 .

[21]  B. Dobson,et al.  A Review of the Indirect Calculation of Excitation Forces from Measured Structural Response Data , 1990 .

[22]  Peter Möller,et al.  Load Identification Through Structural Modification , 1999 .

[23]  N. Giansante R. Jones,et al.  Determination of In-Flight Helicopter Loads , 1981 .

[24]  Fu-Kuo Chang,et al.  Real-time impact identification of stiffened composite panels , 1999, Smart Structures.

[25]  H. R. Busby,et al.  Impact force identification using the general inverse technique , 1989 .

[26]  J. Fabunmi.  Effects of structural modes on vibratory force determination by the pseudo inverse technique , 1985 .

[27]  F. D. Bartlett,et al.  Model Verification of Force Determination for Measuring Vibratory Loads , 1979 .

[28]  S. Karlsson,et al.  IDENTIFICATION OF EXTERNAL STRUCTURAL LOADS FROM MEASURED HARMONIC RESPONSES , 1996 .